The vibrant commerce between California and Mexico is reflected at the commercial truck crossing in San Diego. A more robust partnership with our southern neighbor would have benefits on both sides of the border.

Americans are intensely aware that China, with its rapid growth and expanding middle class, will probably have a bigger economy than ours within a decade or two. But few Californians are aware that the growing Mexican economy, with its own expanding middle class, will probably surpass our state's economy.

The moment of Mexican triumph might come sooner than we think. California now has the eighth largest economy in the world. Mexico has the 14th largest, but Goldman Sachs projects that by 2050, Mexico's will be the fifth largest economy on the planet - having blown past California's long before that.

Yes, such rankings are mostly symbolic: Mexico's people (119 million today), will still be poorer on average than California's. But if Mexico has a bigger profile on the world stage, we might find ourselves in its shadow. So Californians would be wise to start thinking differently about our neighbor. Right now, when we do talk about Mexico, we obsess on chronic, mutual problems - unauthorized immigrants, drugs and violence. As a result, there's been little discussion of Mexico's rise or of how we can prosper from it.

We'd be better off thinking about Mexico as California's China - a vital economic partner that's also a competitor, a society that is rapidly advancing even as it remains dogged by poverty and corruption.

Mexico is gaining in areas in which we need help. California could find a new economic engine in the continuing growth in Mexico, which is already our largest export market. California is desperately short of engineers and technically skilled workers, and Mexico is producing more engineers than California (and nearly as many as the entire United States). California needs more college graduates and has cut state funding to its university systems - even as Mexico has doubled its number of universities in a decade.

"Mexico is less a problem and more an answer for the economic, security, and international diplomatic challenges the United States faces today," writes Shannon K. O'Neil of the Council on Foreign Relations in her book, "Two Nations Indivisible."

All this is not news to California business and political elites, who have been supportive of the exchange of people, goods, services and ideas between California and Mexico. But these flows across the border remain somewhat haphazard and underappreciated.

"The overlap of California and Mexico encompasses communities, but it is not in itself a community," wrote political scientist James N. Rosenau 20 years ago in an essay in the book "The California-Mexico Connection."

Rosenau's words still apply today, in part because California has never had a Mexico policy. Instead, we've dealt with the impacts of our relationship with Mexico piecemeal, leaving a void too often filled by counterproductive measures - the 1994 anti-immigrant ballot initiative Proposition 187; disputes over pollution and crime; additional border enforcement that chokes commerce.

A California policy of seeking deeper cooperation - and shared governance - with Mexico would change the game. What if we worked with the Mexicans to rebuild our infrastructure, which would boost trade? We could develop new environmental regulations jointly, and in the process reduce abuses of the California Environmental Quality Act. We could offer in-state university tuition to Mexicans who can demonstrate financial need, as Texas does. And with both Mexico and California needing more college graduates, why not open a University of California campus in, say, Ensenada?

To start with, and for no money at all, California's media and civic leaders could add Mexico to their campaign platforms, debate dockets and political polls - up there with schools, health care, prisons, water and jobs.

There has been no shortage of ideas for helping California and Mexico build community. Foreign policy scholar Abraham Lowenthal has suggested creating a joint California-Mexico online database for the school records of children who move between the two countries. There have been fledgling efforts to cooperate in tourism (joint marketing of both places, particularly to Europe and Asia); law enforcement (not just prosecutions but also collaborations around judicial reform to bolster the rule of law); and in health care (cross-border markets to reduce pharmaceutical prices and to control costs).

But such ideas haven't gotten very far. The cause of California-Mexico partnership has been unlucky in its political champions, including a recalled governor (Gray Davis) and a disgraced San Diego mayor (Bob Filner). And California's leaders have tended to leave Mexican relations to the federal government, a mistake given Washington's paralysis and dysfunction.

The methods of cooperation could be many, but the overriding goal should be to turn California and Mexico into - to borrow a phrase used by the Europeans in their own integration - a single "economic community" and ultimately a union. The logic is simple: If you can't beat Mexico, join it.